Method of molding glass articles



April 29, 1947. R. P. CASSELL METHOD OF MOLDING GLASS ARTICLES FiledDec. 17, 1943 3 Sheets-Sheet l fioberti zafisell a, 413%? To? 41% April29, 1947.

R. P. CASSELL Filed Dec. 17, 1943 QUIZ METHOD OF MOLDING GLASS ARTICLES3 Sheets$heet 2 INVENTOR M Jiobertf Cass ell April 1947. R. P. CASSELL2,419,764

METHOD OF MOLDING GLQSS ARTICLES Filed Dec. 17, 1943 3 Sheets-Sheet 3INVE-NTOR of the sign or marker.

Patented Apr. 29, 1947 UNITED STATES PATENT QFFIC'E METHOD OF MOLDINGGLASS ARTICLES Robert P. Cassell, Jeannette, Pa., assignor toflfhe"Jeannette Glass Company, Jeannette, Pa., a

corporation of Pennsylvania Application December 17, 19,43, SerialNo.-514;693

I "'5Claims.

.1 This invention relates to a method of pressmolding glass articlesand-particularly to amethod of molding glass articles the: relativeshape an volume of which render-the molding diflicult. .The glassarticle-to whichthis invention pri- .marily is directed is a reflector buttonof'the sort used in signs and markers disposed along roadways. Thosebuttons are exemplary of glass articles which are solid. bodies ofglass-havingan enlarged or flanged central portion and two additionalbody portions extended oppositely from the central. portion of the body.In glass reflector buttons, the press-molding of which is illustrated,each of such articles has a laterally extendedcentral region in the formof a fiange, and two end or, shank portions extended axially in oppositedirections therefrom. In-use of such. button,

one of its. shank portions serves foranchorage in a metal plate or thelike which forms the base The flange provides a division. line fromwhich .in -mounted position there extends a rounded boss orbutton whichchiefly provides .the reflecting surface.

Considering such articles as exemplary, great difiiculty is encounteredin molding them, automatically to form. The body is small and-solid,

thus comprising a relatively. great- Weight. and

volume of glass with respectto its overall size, and'the extendedcentral region or flange'presents a complication in the preparation ofamold cavity for press-molding thebutton. For-this reason, such buttonshave previouslybeen made at considerable, expense .by molding the entirearticle to the extreme diameter of, its central region, or flangahandthen grinding down the two extended, Orshank, portions to adiameter-less "than that of the" flange.

The object of this invention is to provide a "method by which reflectorbuttons of the sort described, and analogous lass articles, may bepress-molded accurately and rapidly to their desiredfinal' forminautomatic machines which are primarilyof conventionalstructure, and inmolds of simple design and'arrangement.

' jThe invention may best be understood by consideringthat specificarticle, namely a reflector "button, as exemplary, and by reference tothe accompanying drawings exemplary of apparatus embodiments. inwhichthe method ofthe invention maybe practiced.

In the drawings: "Fig; I'is a' plan view ofv a rotarymold-carrying*tablearranged to .be moved. step by. step, sequeni'tia lly to; index.each of. a plurality of molds car- 'ried by the table at a plurality'ofworking stations; this figure of the drawings showingstations in whichthe novel steps of my method. are performed, and "showing molds arrangedforthe press-molding of glass articles in accordance with those novelsteps the glassto .be moldedandthe articles to be molded therefrom beingomitted in this figure of. the drawings.

Fig. II is taken in the-planeof the arcuate sec- ,tion line IIII andshows a .vertical sectional development of the mold-carrying table,molds thereon, and associated structure illustrating the movementandposition of those elementsin the same several stations'shown in Fig,I; the steps of the processbeing.illustrated in this figure of thedrawings by showing the feeding of amold charge at one of the-stationsto which 'thetable is-brought and-the formation and discharge; of theformed article. at other stations; and this figure of-the drawings alsoshowing'inelevation in the plane ofsection 1ineIV'IV of Fig. III; and

position of elements occurring in,;thesame *station shown in Fig.IIL-but taken at right angles thereto,.and showing thecam-trackincross-section.

The, exemplary structure showninthe drawings comprises ajcircularmold-carryingtable l which it i to be understood is rotated step by stepthrough a pluralityof forming stations ap- 'propriate to thepress-molding ;of, articles; from mold charges of-.molten;- glass. Fig:I;;-s ho ws; a plurality of moldassembies Zand illustrates-thepositioning of the molding;;assemblies-, at;five stations towhich eachof'the molds is indexed in step. by step rotation ofthemold-carryingtable.

These stations are designatedrespectively A,- B,

.C, D,- and E, and Fig. II-of the drawingsshows five likemoldassembliesoccupying the same several stations as in Fig. I. -Itis;to b e;understood that thetmove'ment of the moldcarrying table.- is

clockwise as. is indicated in Fig. I, and-the table movement in Fig. IIis similarly from right to 4 conventional, it being common practice inthe art to discharge formed articles from a mold by raising in thecavity of the mold a plunger, or bottom mold element.

It will be noticed that in station A the upper portion of the solidformed article projects beyond the upper level of the die. A sufficientweight and volume of molten glass, to provide the mold charge for sucharticle cannot, therefore, satisfactorily'be received in'a' die cavitydimensioned as shown in station A, because the fluid glass is the finalone of a plurality of cooling stations through several of which thearticle passes after it is molded. Station B is a. discharging stationfor the article. Station is a cooling station for the mold from whichthe article has been discharged, and a preparation station in whichele-" ments of the mold assembly are prepared for the reception of thenext mold charge of molten glass. Station D is a feeding station inwhich a chargev of molten glass is fed to the mold elen ents carried byor directly associated with the mold-carrying table I. station in whichthe article is formed to the desired shape by the cooperative action ofthe moldl ing and pressing elements of the forming assem- Station, E isa forming bly.

Referring to the several figures of the drawings, the; mold assemblyconsists primarily of a mold bodyor die 4 mounted on a flanged base 4acarried by rotary table I. The formation of the die cavity is that of acircular bore of uniform 'diameter throughout approximately its height,

but at its upper end this bore is extended laterally in a region 6 toprovide for the flange or lateral extension on the body to be molded,and above this lateral extension 6 there is a further extension 1providing space and a seating shoulder for the forming head of a topforming plunger 8. In the mold base 4a below mold body or -die 4 thereis a bore of extended diameter in which is slidably mounted a stem 9carrying bottom plunger ID. This plunger; or movable mold element, isslidable in the bore, or shank-forming cavity, 5 of the mold body ordie. At its lower end stem 9 is provided with a roller II which ridesonthe surface of a cam-track 12. All the molds of the apparatusare'identical in structures Considering first station A, in that stationbottom plunger I0 is in its normal or forming position in which itprovides the bottom element of themold, and cooperates in defining themold cavity. In this position, roller II on the stem of the bottomplunger rides on a surface I 2a which may be considered to lie at thenormal elevation for the cam-track. The formed arti- 'cle"'3, which hasbeen cooled preparatory to its discharge, lies in the cavity of the moldwith the lower convex end of its shank portion 3c lying in the concaveupper surface Illa of the bottom plunger. Flange 3a of the article liesin the 'lateral extension 6 adjacent the upper end of the die cavity,and its shank 3b extends upwardly beyond the upper end of the die.

To discharge the formed article 3 in station B, roller H of the plungerstem rides up to the surface [21) on an elevated lobe of the camtrack.This upward movement of stem 9 raises and volume of the die cavity thatit can accom- 'modatea complete mold charge.

This I do by causing retraction of plunger I 0 to a. position below itsforming position in the main shankforming region, or bore, 5 of the moldcavity. In the exemplary means illustrated, the plunger is retractedby'causing roller H on plunger stem 9 to ride down from lobe l2b of thecam-track to a depressed region l2cd which lies at a level below thenormal forming level of region l2a. Station C shows the mold assembly inthi position with plunger l0 retracted to increase the effective depthand volume of the die cavity.

This station serves as a preparatory station in which the mold elementsare brought into feeding position and are cooled to a temperaturesuitable for contact with the charge of molten glass.

From station C the mold assembly is indexed to feeding station D, theroller I I of the plunger stem still riding in the depressed region l2cdof the cam-track. In station D, plunger [0 thus still remains in itsretracted position assumed in station C, as the bottom of a mold cavityof increased depth. Into this cavity a mold charge M, as indicated inFig. II of the drawings, is fed to the mold body or diethrough afunnel13,

To form the article, and after the mold charge has been fed to the die,I define in the'pressmolding assembly a completely closed cavity whichincludes a cavity in the head of top forming plunger -8 and which isshaped and dimensioned suitably for forming thedesired article. Theprocedure of so doing will be described as it may be performed in theexemplary apparatus shown and described.

As the mold containing mold charge M is indexed forward from stationDlto station E, roller H on plunger stem 9 rides up to a region I2e-ofthe cam-track which is at the level of the cam-surface lZa at station A.This raises bottom plunger l 0 into forming position in which itprovides the bottom of a mold cavity dimensioned appropriately to theformation of the desired article. As bottom plunger In rises, topplunger 8 descends to a position in which its annular nose l4 lies inthe shoulder of extension 1 in the mold body, and the cavity [5 in-thehead of the plunger receives that portion ofthemoldjcharge whichAlthough top plunger ti'cannot Q be positioned on the ITIQIIZOIltdIlKmoying mold assembly untiiithat "mol'd'i with the formedarticle thereinis indexed to a cooling station, or stations. It has been-assamba abovethat the "table indexes the molds at but one forming station ineachcomplete revolution of the table, the surfaces |2a and In being regionsat'the'endsbf a uniformly elevated *arcuate region of the cam-track.When, how- "evenf small articles {such as the exemplary reflect'orbutton,- are molded, "it frequently is pos- "sible' to repeat the method'of the' -in'v'entio n in "each revolution 'of the exemplary mold carr-yiriga 't'able, Icy-providing more than onetopplunger and 'byrepeating the 'cam' contounwhich gives determinate movement to thebottom plunger.

"It 'Will be seen that the essential steps of the method are toincrease'the volume of the die cav-f 'ity' by increasing its -depth fromthebottom'so that it can 'acccmmodatea mold charge comprising a greaterweight and'volume of molten glass than would otherwisebe'possible andthen pressmolding the glass while 'restoring't-he dimension 'of the diecavity in the dieitself and efiectively extending the volume of thetotal mold cavity by providing for flow of the 'charge into a cavityprovided in the pressing instrumentality which is cooperative with thedie.- In the exemplary organization shown for forming the specific--article taken'asexernplary, an" extension of the fmold cavity isprovided in formingposition of the' elements'to give a concaveend-surface to the shank 'of the amide formed in that region of themold. This, "however, isspecific" in "its nature andis appropriate t thespecific article taken as illustrative. -Since'the main portion of themold cavity, i. e., the cavity '5 in die 4, is capable of formingstructure'in the nature of a shank,

leg, boss, or the like, it is unnecessary that such cavity be providedas in the upper-face of a bottom plunger. The upper surface of thebottom plunger maybefiatfconvexor may bear any suitable design, as isappropriate to the specific article which is formed. Itis,however,"essential that a cavity for upward flow of the mold chargebe provided in the pressing instrumentality; that is, in the head of apressing plunger or in some adjunct structure associated With theplu'ngenas 1 Well as-that the bottom plungerbe arranged for verticalretraction below its forming position in the die cavity.

The method of the invention as illustrated is performed in a rotaryglass-forming machine in which each of the molds is indexed at acircularly arranged sequence of stations, and a specific molding andpressing organization is shown and described. It is, however, to beunderstood that the method of my invention may be performed in apparatusof various other types and in molding and pressing organizationsdiffering widely from the one herein shown and described. The essentialsof the method have been above given, and as indicated, the method itselfis susceptible of substantial variation in its performance.

The disclosure of apparatus embodiment for performing my method beingexemplary and the disclosure of the methodsteps herein made being inmeasure exemplary, I do not intend to limit -my invention to"meansptiliZed in perfor iiiifig' tlie "method; "ports the specific"prrcrmahce orthe 'I'flthdd 'h'erin disclosed" Other bhifi by the'dfini't'ion of tlie 'cIai-ms appendedliereto.

5 rclai masmy mverinon: V

1. In the'pr'ess-moldifig bfagl'as's airticle 'which comprisesalaterally extcndedfifltrln'diate per- "tiin "with two end or shankportions extended- 6p- "pfisitely" therefrom the heiein -fis'i'ibd lnthid 10 of molding siich article ina'mold assembly ens-mp'i'ising a 5'diefhav ing therein on f shank-molding iiavity and'at the openfiipper ed heresf-anex- "tension of such cavity for forming the latefall'yextended intermediatepbruenbfthe article and "a" top fo'rmirig pluiiger'havingtherein a -"cavity for forming the other shank portion of the a r-ticle,' which "comprises first'mreasmg the charge- 'rebeiving volume 6fthe -die*c"aivity beytincl' the 'volume' 'of that portionof theart-icle' which is to formed therein by increasin the charge receiv'ingdepthof thedie cavity beyond the dpth thereof 'at which 'the 'saidcavityis efi'ec'tive regionaIIytO form the said glass {article -from" 'thecharge; feeding to and vvh6lly-receiving in the die cavity {Jr-charge'of mo ten glass s'uJcsta'riti ally equal in volume to thevolume "of thefinished article, 'pr'ess' molding fineness;- by restoring-"the"diecavity to its effective charge-forming dimensions witli" a portionof the-charge of molten glass 'extendingabove the saidcavity,*andforniing the said article by rapidly relating -'the saidtopforrning-plungenwith the said die to -inove the upwardly extended"portion' of the charge-into the cavity of t-hesaid plu'nger.

'2. In the press-mbldingof a glass articlevvhich comprises alaterallyi'ext ended intermediate portion with two end o'r'shankportions extended "oppositely therefrom; the herein described method ofmolding sucharticleina'mdd assembly-com- --prisinga die h'avingther'einone shank molding 'cavity and at "the upper 'endth'ere'of an'extension- "of such cavity for formingthe laterally' 'extendedintermediate portion of the article i and a" top-forming plunger-havingtherein a cavity for forming f the other shanli portion of 7 the-article; which comprises first increasing the cha'rge- 'receivingvolumeof the 'die' cavity beyond the vol- "hrne "of thatpo 'rt'ion' 0f thearticle which is to l be'foirmed therein by lowering a charge-supportingsurface in the die 'cavityto thereby increase "the charge-receivingdepth of the" die cavitybeyond the depth the'reof {at which the said'cavity is effective regionally to form the 's'aidglass article from thecharge, feeding to and wholly fis're'ceiving in the die cavitya-chargeo-f molten glass substantially equal in 'volume to the volume ofthe finished article, press-molding the glass by raising thecharge-supporting surface of the die to restore the die cavity to itscharge-forming di- 50 mensions with a portion of the charge of moltenglass extending above the said cavity, and forming the said article byrapidly relating the said top-forming plunger with the said die to movethe upwardly extended portion of the charge into 5 the cavity of thesaid plunger.

3. In the press-molding of a glass article which comprises a laterallyextended intermediate portion with two end or shank portions extendedoppositely therefrom; the herein-described meth- 0d of molding sucharticle in a mold assembly comprising a die having therein oneshank-molding cavity and at the upper end thereof an extension of suchcavity for forming the laterally extended intermediate portion of thearticle and a top-forming plunger having therein a cavity for formingthe other shank portion of the ar- ;-t ic1e, which comprises firstincreasing the charge- .li'eceiving volume of the die cavity beyond thevolume of that portion of; the article whichis' to be formed therein bylowering a' charge-supporting surface in the die cavity to therebyincrease the charge-receiving depth'of the die cavity beyond the depththereof at which the said cavity is effective-regionally to form thesaid glass article from the charge, feeding to and wholly re-,

ceiving in the die cavity a charg of molten glass substantially equal involume to the volume of the finished article, press-molding the glass byraising the charge-supporting surface of the die -to restore the diecavityto its effective chargeforming dimensions with a portion of thecharge ,of molten glass extending above the said cavity,

ing a die having therein one shank-molding cav-' ity and at the upperend thereof an extension of such cavity for forming the laterallyextended intermediate portion of the article, a bottomforming plungerreciprocable in the said die cavity to provide the charge-supportingsurface thereof and a top-forming plunger having therein a cavity forforming the other shank portion of the article; the herein-describedmethod of molding such article which comprises first increasing thecharge-receiving volume of the die cavity beyond the volume of thatportion of the article which is to be formed therein by lowering thesaid bottom-forming plunger to thereby increase the charge-receivingdepth of the die cavity beyond the depth thereof at which the saidcavity is effective regionally to form the said glassarticle from thecharge, feeding to and wholly receiving in the die cavity a charge ofmolten glass substantially equal in volume to the volume of the finishedarticle, ress-molding the glass by raising the bottom-formin plunger inthe die cavity to restore the die cavity to its effective charge-formingdimensionswith a portion of the charge of molten glass extending abovethe said cavity, and forming the said article by rapidly 'relating'thejsaid top-forming plunger with the .said die, to move the upwardlyextended portion ofrthe chargeinto the cavity of the said plunger. 5. Inthe press-molding of a glass article which comprises a;late rallyextended intermediate portioniwith .tWQend'or' shank portions extendedoppositely therefrom, in a mold assembly comprising a die havingthereinone shank-molding cavity and at the upper end thereof an extension ofsuch pavity-for forming the laterally extended. intermediate portion ofthe article, a bottom-forming plungerreciprocable in the said die cavityto 'providethe charge-supporting surface thereof and" a-topformingplunger having therein a cavity for forming the other shank por- .tion Othe article; .the herein-described method of molding such article whichcomprises first increasing the charge-receiving volume of the die cavitybeyond thevolume of that portion of the article; which is tobe formedtherein by lowering the said bottomforming plunger to thereby increasethe charge-receiving depth of the die cavity beyond the depth thereof atwhich the said cavity is eifective regionally to form the saidglass-article from the charge, feeding to and wholly receiving inthe'die cavity a charge of molten glass substantially equal in volume tothe volume of the finished article, press-molding the ,glass by raisingthe bottom-forming plunger in the die cavity to restore the die cavityto its effective charge-forming dimensions with a portion of the chargeof the molten glass extending a above the said cavity, forming the saidarticle by rapidly relating the said top-forming plunger with the saiddie to move the upwardly extended portion of the charge into the cavityof the said plunger, removing the said top-forming plunger fromcooperative relation-with the die, and raising the bottom-formingplunger beyond its charge-forming position in the die cavity to elevatethe molded article above the die.

ROBERT P. CASSELL.

REFERENCES CITED Number Name Date 810,570 Sages n Jan; 23, 1906"2,233,057 Luce Feb. 25, 1941 V FOREIGN PATENTS Number Country DateBritish Mar. 7, 1939 Y 50l,865 I t

